2003 Volume 52 Issue 7 Pages 352-357
Si diffusion layers on SUS 310 steel surfaces were formed by halide-activated pack cementation, and their high temperature corrosion resistance was evaluated. The Si diffusion layers formed in the sample surfaces consisted of an inner layer and an outer layer. The inner layer contained 11-12 mass% Si was uniform and adhesive to the substrate metal. It was found from XRD analysis that the inner layer consisted of two phases of α-Fe and Cr3Ni5Si2. The thickness of the inner layer increased with an increase in the treatment time and a rise in the treatment temperature. The inner layers of 60-80μm thickness were obtained by the treatments for more than 28.8ks at 1223K. The results of high temperature corrosion experiments showed that the corrosion resistance of the sample having Si diffusion layer was greatly improved by the formation of a protective inner scale consisting of SiO2.